Type-writer escapement.



N0. 800,801. PATENTED OCT. 3, 1905. E. J. FAIRFIELD.

TYPE WRITER ESGAPEMENT.

APPLICATION FILED MARJO, 1902.

UNITED STATES PATENT OFFICE.

EDMUND J. FAIRFIELD, OF HARTFORD, CONNECTICUT, ASSIGNOR OF ONE- THIR-DTO AUSTIN C. DUNHAM AND ONE-SIXTH TO PHILANDER C. ROYCE, OF HARTFORD,CONNECTICUT, AND ONE-SIXTH TO M. BRAD- FORD SCOTT, OF WEST HARTFORD,CONNECTICUT.

TYPE-WRITER ESOAPEIVI ENT.

Specification of Letters Patent.

Patented Oct. 3, 1905.

Application filed March 10, 1902. Serial No. 97,424.

To all whmn it may concern.-

Beitknown that I, EDMUND J. FAIRFIELD, a citizen of the United States,and a resident of Hartford, in the county of Hartford and State ofConnecticut, have invented certain new and useful Improvements inType-Writer Escapements, of which the following is a full, clear, andexact description, whereby any one skilled in the art can make and usethe same.

This invention relates to the class of escapements which are embodied ina type-writing machine in which there is a power-driven carriage, themovements of which are controlled by keys through the medium of anescapement 5 which is operated by the movement of the keys or theuniversal bar of the machine.

The object of the invention is to provide for a type-writing machine anescapement that can be used at a fast or slow rate of speed and yet havethe carriage completely under the control of the operator; and a furtherconsideration is the simplicity and cheapness of the structure for thepurpose intended.

Referring to the accompanying drawings, 2 5 forming part hereof, Figure1 is a top View of the escapement,with parts of the type-writing machineto which it is applied broken away. Fig. 2 is a view in elevation,showing the escapement in normal position for use. Fig. 3 3 is a view inelevation of the escapement illustrating the position of the parts whenthe normally disengaged dog is thrown into engagement with theescape-wheel.

The escapement forming the subject-matter of my invention is adapted tobe used in a type-writing machine of ordinary construction in whichthere is a toothed bar, sometimes called the rack-bar, usually borne ona power-impelled carriage, and as the general 4 construction of suchmachines is well known in the art only so much of the parts isillustrated herein as to enable the relation of the escapement device tothe mechanism of the type-writing machine to be understood.

In the accompanying drawings the letter a denotes the rack-bar of apower-impelled carriage of a type-writing machine, to the frame of whichthe escapement b is attached in any convenient manner.

In the preferred form shown there is a bracket 0, arranged to beremovably secured to a part (Z of the frame of a type-writing machine,and on this bracket or base-piece is mounted a rotary shaft 0 in asuitable bearing f. On this shaft 6 is a pinion g, the teeth of whichare in mesh with the teeth of the rack a in such manner that the rotarymovement of the shaft will permit a movement of the rack-bar and theplaten-carriage which supports it. On the outer end of this shaft 0 isan escape-wheel it, the teeth of which have bearing-surfaces in linesparallel to the axis of the shaft. These teeth h are preferably in theform of pins, as illustrated in the drawings. On the bracket 0 two loosepawlst'and 1 6 are pivotally mounted, so as to swing in planes whichcross the line of the axis of the shaft. The pawl t has a detent-tooth2', ar-

ranged to lie in the path of rotary movement 1 of a tooth h and to holdthe escape-wheel in a position of rest when the pawl is in its normalholding position. The other pawl has a deten t-tooth is, which in therocking movement of the pawl is swung forward across the path ofmovement of one of the teeth it just previous to the moment when anothertooth is about to be released by the swinging movement of the pawl t'.The pawl 76 has an arm on which a collar Z, Fig. 2, is pivoted, andthrough this collar a connecting-rod on extends from the universal baror that movable part of the mechanism of the type-writing machine whichis actuated by the movement of the key-levers in printing. The collar Zis connected to the rod in any convenient way, as by being held betweenadjustable collars Z and Z which are arranged to be clamped to the rodm, as by means of screws, as shown in Fig. 1 of the drawings.

A pawl-spring n is supported on the machine or attached part with oneend arranged so as to hold the pawl t' with a yielding pressure in itsposition to engage a tooth of the escape-wheel and prevent rotarymovement of the latter. On the other pawl it a trip 0 is mounted, andthis is preferably in form of a screw which extends through a threadedsocket in a stud 0 fast to the pawl is. When the pawl 7c is moved, as bydepressing the keylever, the end of the trip strikes against the pawl 2'and forces the detent-tooth t out of engagement with the tooth h of theescapewheel. By this same movement the detenttooth 7c is swung intoposition in the path of rotary movement of the teeth of the escapewheel,so that when one of these teeth is re leased from the hold of the pawl11 the detenttooth on the pawl X: will be in position to arrest therotary movement of the wheel and hold the carriage in the properposition to receive the impact of the type in printing. This imprint ofthe type takes place between the release of one tooth 71. of theescape-wheel from the detent-tooth v," and the engagement of thisdetent-tooth 2 with the next succeeding tooth ot' the escape-wheel, thecarriage being held in this intermediate posit-ion by the engagement ofthe detent-tooth Z." with a tooth 72/ in substantially the position asillustrated in Fig. 3 of the drawings. The keylever is depressed in theact of printing, and when the downward pressure upon the key is removedthe releasing movement reverses the direction of tilting movement of thedetent lever or pawl and disengages the detentto0th 70 from a tooth ofthe escape-wheel, so that the parts pass from the position shown in Fig.3 to that shown in Fig. 2, except that the escape-wheel has rotated onetooth-space and the tooth 71 engages the tooth 72 on the escape-wheelnext in rear of the tooth it with which it was engaged at the beginningof the movement described.

Of the two loose pawls used in the embodiment of my invention one, as 2is normally engaged with a tooth of the escape-wheel and the other, asZ1, is normally disengaged.

A trip device or equivalent construction that enables the movement ofthe normally disengaged pawl to move the other pawl out of engagementwith a tooth of the escapewheel forms a feature of my invention. Thistrip device is shown as a separate element; but that is not essential.

It is not necessary that the two pawls should be made of the preciseshape or should be arranged precisely as shown in the accompanyingdrawings, as various modifications as to the manner of engagement of thepawls and their relative arrangement with reference to the escape-wheelmay be made without departing from the invention or requiring more thanthe exercise of mechanical skill, and such changes are within the intentand scope of my invention.

My invention as illustrated, described, and claimed herein consists,broadly, in the mounting of two pawls upon the same axis and acting inconnection with a rotary escape-wheel, one of said pawls having acertain movement independent of the other and a trip upon one of thepawls adapted to engage and move the other of the pawls, the pawls beingconfined in their movement to one side of the axis of oscillation.

I do not claim the special arrangement or form of the teeth on theescape-wheel, nor any special arrangement of the pawls with respect tothe escape-wheel, nor the manner in which the pawls shall receive theforce from the escape-wheel, nor the shape of the bearing-face oi thepawls, nor the special arrangement and construction of the trip device,these features having been invented by Edwin H. Dodge, whose applicationwas filed on the same date as that of which my within application wasfiled.

IVhat I claim as my invention, and desire to secure by Letters Patent,is-

1. In combination with a rotary escapewheel having d etent-teeth, anormally engaged detent-pawl with its tooth normally held in the path ofmovement of the detcnt-teeth on the escape-wheel, a normally disengagedpawl with a dctent-tooth, each of said pawls supported upon the sameaxis for movements independent of the other, and one of said. pawlsadapted to be engaged and moved by the other.

2. In combination with a rotary escapewhecl having detent-teeth, a normally engaged detent-pawl with its tooth removably held in the path ofmovement of the detent-teeth on the escape-w heel, a normally disengagedpawl with a detent-tooth arranged to successively act upon the teethengaged by the normally engaged detent-pawl, a trip device mounted onone of the pawls and arranged to engage the other pawl in itsdisengaging movement both of said pawls mounted upon the same supportand having coincident axes of oscillation, and means for actuating thepawl bearing the trip device.

3. In combination with a rotary escapewheel having detent-teeth, anormally engaged detent-pawl with its tooth removably held in the pathof movement of the detent-teeth on the escape-wheel, a normallydisengaged pawl independently mounted with respect to the engaged pawlbut on the same support and having a tooth arranged to successively actupon the teeth of the escape-wheel engaged by the normally engaged pawl,a trip device mounted on one of the pawls and arranged to engage theother pawl in disengaging the normally engaged pawl, both of said pawlshaving the same axis of oscillation and means for actuating the pawlbearing the trip device.

4. In combination with a rotary escapewheel having detent-teeth, apivoted detentpawl with its tooth removably held in the path of movementof the detent-teeth on the escape wheel and arranged to be operated by atrip device, the trip device mounted on one of the pawls, anindependent]y-pivoted disengaged pawl with a detent-tooth, both of saidpawls being mounted upon the same pivot and having movements independentof each other, and means for actuating the pawl bearing the trip device.

5. In combination with a rotary escapewheel having dctent-teeth, a pairof pawls having detent-teeth, the tooth of one of said pawls normallyengaging a tooth of the escape-wheel, and the tooth of the other of saidpawls normally out of engagement with the teeth of the escape-wheel,said normally disengaged pawl and normally engaged pawl havingcoincident axes of oscillation, the tooth upon the normally disengagedpawl having engaging and disengaging movements always at one side of theaxis of oscillation. 6. In combination with a rotary escapewheel havingdetent-teeth, a normally engaged pawl with its tooth normally inengagement with a tooth of the escape wheel, a normally disengaged pawlwith a detent-tooth, means intermediate the normally disengaged

